Method of purifying water.



W. B.` BULL. METHOD 0F PURIFYING WATER. A PPLIOATION FILED MAY 31. 1910.

.Pannd Jan. 24, 1911.

' IN1/Ewan wu A Mfrs.

` UNTTED STATES PATENT oiuncn.-

WILLIAM B. BULL, OF CHICAGO, ILLINOIS, ASSIGNOR TO CHLORIDE PROCESS COMPANY,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

METHOD OF- IURIFYING WATER.

Patented Jan. 24, 1911.

Application filed May 31, 1910. Serial N0. 564,245. I

' following is a specification, reference being had to the accompanying drawings.

My invention'relates to the purification of Water for potable and other industrial uses,4

and; it has particularly to do with the puriication of Water in large quantities by treating the water with a suitable coagulant adapted to agglomerate or cause a coales- -4 fore been most generally used, and particucence of the impurities in the water and afterward removing the coagulated matter by sedimentation or by filtration through a granular filter-bed.

The object of my invent-ion is to provide a new and improved method of treatment which will be so economical as to be commerciallypracticable, and in which it will not be necessary to use slaked lime or limewater.

Some of the methods which have heretolarly within the last few years, have comprised the introduction into the water to be purified of a suitable soluble metallicsalt, such as ferrous sulfate, and the precipitation of the iron` in the form of a hydrate by the usevof slaked lime or lime-water. While the results obtained by this method are very satisfactory so far as the removal of the impurities contained in the water is concerned, lthe use of the lime solution has been followed with very serious consequences due to thefact that the lime is deposited upon pipes, valves'and fittings and in the lter-bed so that the efficiency of the plant is soon very considerably reduced 4and ultimately is practically destroyed. My improved process is free from this object-ion and then coagulating the impurities in the water by the use of such coagulant. It also and besides may be practiced much more economically than the iron process described.

It consists in producingby electrolysis a solution which is a solvent of iron, subjecting iron in a separate chamber to the action of such solution to 'formv a solution of an iron compound, precipitating the iron solution in the forn'of an hydroxid coagulant,

contemplates the formation bythe electrolytic act-ion of an alkaline hydrate, and the its agglomeration would take p ace in such water. i

In the accom anying drawings, which illustrate a simp e form of apparatus for practicing my process, the figure is substantially/a central vertical section.

Referring to the draWings,-1 indicates a suitable receptacle, which is divided by a porous diaphragm 2 into anode and cathode compartments 3,4.

5, 6 indicate electrodes of which the positive oryanode is of carbon or other suitable material chemically inert so far as chlorin is concerned, which are placed in the two compartments 3, 4, respectively, and are connected to conductors 7, 8 by which the electric current is sup lied.

9, 10 indicate 1n et pipes communicating, respectively, with the bottom of the chambers 3,- 4. A solutionv of common salt is placed in compartment 4 and the other compartment is filled with Water which at the beginning of the operation may be acidulated, or otherwise treated, if desired, to increase its conductivity.4 With the passageV of the electric current through the wires 7, 8 the electrode 5 becomes the anode and the `electrode 6 the cathode of an electrolytic apparatus, the result being the decomposition of the common salt solution in the compartment 4,'forming a solution of sodium hydrate therein and rthe formation of a solution containing chlorin in the compartment 3. While the operation is in progress c the supply of water and sodium chlorid in the two compartments, 4, is maintained through pipes 9, 10.

1l indicates a pipe leading from the upper portion of compartment 4to a tank 12 vthrough which the water to be purified is passe such water being admitted to the bottom of the tank through van inlet pipe 13.

14 indicates an outlet pipe communicating with the tank 12 near the upper 'portion thereof and at the opposite side from the inlet pipe 13 so that the water to be purified fiows through said tank in an upward direction.

15 indicates a funnel-shapedv receptacle, which is placed in the'tank 12 and with its upper margin below the upper edge of said tank so that the overflow from the solution passing upward through such receptacle, as hereinafter described, is discharged into `said tank. The receptacle 15 is adapted to contain comminuted iron `or its equivalent and is connected at its lower end by a pipe 16 with the upper portion of the chamber 3, the arrangement being such that the overflow from said chamber 3 passes down to the bottom of the receptacle 15 and then up- Ward'through said receptacle, overflowing its upper edge as illustrated in the draws'` ings. It will be apparent that by this construction the iron solvent formed in the chamber 3 will beconducted to the bottom of the receptacle 15 and will rise through the mass of iron in said receptacle, lthereby thoroughly subjecting the particles of iron therein to the action of the solution. The result is the'formationfy of a strong solution of chlorid of ironwhich is discharged into the water to be purified passing through the tank 12. I

If the water to bepurified does not contain suificientfree carbonic acid gas to in-y terfere with rthe natural oxidationof the iron solution and prevent its precipitation as iron hydrate, the use of the sodium hydrate formed in chamber 4 as a precipitant is not necessary,.but Lordinarily. it is desirable to use it, and in such case the solution of sodium hydrate may be conducted directly into the waterto be purified through pipe 11, or, ifpreferred, the solution of sodium hydra'te may bedischargedinto the upper Vportion of the receptacle 15 through a pipe 17 indicated by dotted lines in the drawings.

'In` the latter arrangement the sodium hycontrolling the point yof discharge of the In either case the sodium hydrate solution. agglomeration of the precipitated iron hydrate takes place -in the water to be purified, thus enabling it to coagulate the im purities so that they may be readily re-v moved by subsequent filtration or sedimentation.

i It will be understood that my invention, includes equlvalents 'for thev substances named.. y

I am aware that it has heretoforeibeen Iproposed. to purify sewage by `a process involving the production in lthe mass'of sew.-

age to be purified of chlorid of iron and an alkaline hydrate by electrolysis, using anv anode of iron or other materiallcapable of entering into chemical combination with some constituent of the electrolyte7 but my invention differs radically from said process.- According to the prior process referred to the entire mass of sewage is electrolyzed, necessitating the use of an electric current of many times greater voltage, because of its lower conductivity due to its state of dilution, than is required in my process, in which the electrolyte is insignificant in volume as compared with the volume of water to be purified, and consequently I am able to economically employ as-the electrolyte a solutioii the conductivity of which is so great that a current of low voltage may be successfully employed, and this without invjuriously affecting the water to be purified.

taneously by electrolysis, treating iron in aseparate chamber with the solvent so formed,

and then treating the water to be purified by precipitation ,from the iron solution so formed, either with or without the useof the electrolytically formed precipitant referred to. And I also believe myself to be with the unagglomerated coagulant derived l.-

the first in the art to produce a coagulant i solution which is precipitable as an hydroxid coagulant, such precipitation being 1n some cases effected by the action of the substances naturally contained in the water treated and in other cases by the addition of aj suitable precipitant, such as the alkaline hydrate formed as hereinbefore described.

The term chemically inert as applied to the anode is used to indicate only that the anode is not chemically acted upon by the element liberated at the positive electrode,

and does not mean that it must be made of a iron in a separate chamber to the action of such solution to form a solution of an iron compound, precipitating the iron solution in the form of an hydrox'id coagulant, and coagulating the impurities in the water to be vpurified with such coa'gulant.

2. The method of purifying Water, which consists in producing by electrolysis a solution which is a solvent of iron, subjecting iron in a separate chamber to the action of such solution to form a solution of an iron compound, precipitating the iron solution in the form of an hydroxid coagulant, and subjecting the impurit-ies in the water to be treated to the action of such coagulant before it hasbeen agglomerated.

3. The method of purifying Water, which consists in producing by electrolysis an alkaline hydrate solution and a solution which `is a solvent of iron, subjecting non in a iron solution so formed into the water to lution to form a solution be purified.

5. The method of pur1fymg water, which conslsts 1n producing by electrolysis a solution of caustic soda and a solution which is a solvent of iron, subjecting iron -in a separate chamber to the action of the latter soof an iron compound, and then introducing the iron solution sofformed into the water to be purified and precipitating the iron by the use of the Asoda solution.

6. The method of purifying Water, which consists in producing by electrolysis an alkaline hydrate solution anda solution which is a solvent of iron, subjecting iron in a separate chamber to the action of the latter solution to form a solution of an iron compound, and introducing the iron solution so formed into the water to be purified, and precipitating an hydroxid coagulant therein by means of the alkaline hydrate solution.

T. The method of purifying Water, which consists in electrolyzing a saline solution, thereby generating a solution which is a solvent of iron, separately subjecting iron to the action of the latter solution to form a solution of an iron compound, and then treating the water to be purified with said iron solution.

8. The method of purifying water, which consists in electrolyzing a saline solution, thereby generating a solution which is a solvent of iron, separately subjecting iron to the action of the lat-ter solution to form a solution of an iron compound, and then precipitating the iron solution in the form of an hydroxid coagulant, and coagulating the impurities in the water to be purified with such coagulant.

9. The method of purifying Water, which consists in electrolyzing a sallne solution in a divided cell, separately subjecting iron to the action of the solution formed -at the anode to form a solution of an iron compound, precipitating the iron solution in the form of an hydroxid coagulant, and coagulating the impurities in the Water to be purified with such coagulant.

WILLIAM B. BULL. 

